The aim of this grant is the development of a muSI-RIAC instrument that performs recycles immunoaffinity chromatography on a micro scale amount of sample such as urine, plasma or other biological based fluids. This project will synergistically combine the superior attributes of micro immunoaffinity chromatography with the high precision capabilities of micro sequential injection to create a very versatile and low cost instrumental platform for clinical diagnostics and biomedical analysis. The muSI-RIAC instrument will provide clinicians and researchers the ability to screen complex matrices for low abundance target analytes. This device holds great potential in many biomedical endeavors including biotechnology and drug discovery, immunology, and diagnostic clinical analysis. This device will use miniscule amounts of sample and quickly process it through multiple micro-affinity columns to isolate and then sequentially measure for the presence of targeted molecules. Benefits to the public health will impact both advancements in Research discovery as well as conventional Clinical diagnostics. Clinical situations where routine multi-analyte assays are required on pediatric, post-natal, or elderly patients may require excess sampling using conventional techniques. The serious discomfort or danger to the patients health and care can be greatly reduced through the muSI-RIAC instrument's ability to perform all needed assays with a single drop of fluid (e.g. blood, cerebral, spinal or lymphatic fluids). Research discovery is often encumbered by the need to perform multiple component analysis from highly valued yet small amounts of complex samples. For example, recombinant chemistries for drug discovery, archival blood samples, or cellular culture extracts. The ability to screen for low abundant target molecules, isolate, quantitative and retrieve such components would highly benefit the research communities ability to identify and study important bio-analyte interactions that serve to advance their respective fields.